1. Field of the Invention
The present invention relates to low connection force electrical connectors.
2. Description of the Related Art
U.S. Pat. No. 5,161,995 discloses a low connection force electrical connector such as shown in FIG. 3. A circuit board P is inserted into a connection recess in a oblique direction (L) and then turned counterclockwise (M) to the horizontal position for lock while making a spring contact with the contact elements 52.
The contact elements 52 are fitted in channels 51A and 51B formed in the housing 51. The contact elements 52 are made by stamping from sheet metal so as to have a rear connection portion 52A and a semi-circular front contact portion 52B with contact terminals 52B1 and 52B2 at opposite ends. The lower contact terminal 52B1 is positioned more forwardly than the upper contact terminal 52B2 by a predetermined length.
The upper and lower front ends 53 and 54 of the connection recess is offset by the same length as the predetermined length. A depression 55 with a shoulder 56 is formed on the bottom of the connection recess.
When the circuit board P is inserted into the connection recess in the oblique direction (L) with no or light contact with the contact terminals 52B1 and 52B2, the lower front edge of the circuit board P is received in the depression 55 during the insertion and turning operation.
Thus, with such a connector it is possible to connect the circuit board to the connector with low connection force while assuring satisfactory contact between the circuit board and the contact elements.
However, it is necessary to make a depression and a shoulder for receiving and turning a circuit board. The depression makes it necessary to divide the metal mold into several pieces and complicates the manufacture, resulting in the high manufacturing costs.